Tax Audits and Adjustments: Responding When the IRS Questions Your Return

A tax audit is an IRS examination of a tax return to verify that income, deductions, and credits were reported correctly.

Audits come in three main forms that differ sharply in scope and intensity. A correspondence audit is handled by mail and usually targets a few specific items, an office audit is conducted in person at an IRS office, and a field audit takes place at a taxpayer's home or business and is the most comprehensive. Most audits are the narrow, mail-based kind rather than a broad investigation. The table below compares them.

Audits are triggered by a mix of statistical scoring, document mismatches, and certain high-risk items, not usually by random suspicion.

The IRS scores returns for likely errors, and a return can also be flagged when the income it reports does not match the W-2s and 1099s the agency receives. Unusually large deductions relative to income, cash-heavy businesses, and issues found in a related taxpayer's audit can all draw attention, and gift or estate items carry their own audit exposure. Some returns are simply selected at random. Knowing the likely trigger helps focus the response on what the IRS actually questions.

The examination centers on the IRS reviewing records that support the items on the return.

The examiner issues information document requests asking for receipts, statements, and other proof, then compares them to what was reported. If everything checks out, the audit closes with no change, but if the examiner disagrees, the findings are set out in a report proposing adjustments to the tax. Providing organized, responsive documentation is the most effective way to limit or avoid adjustments. Volunteering unrequested information, on the other hand, can widen the audit.

Two letters mark the key decision points once the IRS proposes an adjustment.

A 30-day letter presents the proposed changes and gives the taxpayer the right to appeal within the IRS before anything is final. If the matter is not resolved, the IRS issues a Notice of Deficiency, often called a 90-day letter, which is the taxpayer's ticket to the U.S. Tax Court. Missing the deadline in the 90-day letter can make the assessment final and cut off the option to challenge it without first paying. If you receive either letter, treat the deadline on it as critical and decide quickly how to respond.

Most disputes can go first to the IRS Independent Office of Appeals, and then, if needed, to court.

Appeals is separate from the examiners and can settle a case based on the hazards of litigation, meaning the risk each side would face in court. If Appeals does not resolve it, a taxpayer who received a Notice of Deficiency can petition the U.S. Tax Court within the deadline without paying the disputed tax first. Alternatively, a taxpayer can pay the tax and sue for a refund in another federal court. Choosing the right forum affects both cost and strategy.

Taxpayers have defined rights during an audit, including the right to representation and to appeal.

The Taxpayer Bill of Rights recognizes rights such as being informed, retaining a representative, appealing a decision, and reaching finality. In most disputes the taxpayer carries the burden of proving that the return was correct, which is why records matter so much, though the burden can shift to the IRS in limited circumstances. Keeping receipts, statements, and contemporaneous documentation is often the difference between winning and losing an issue. Strong records turn an examiner's assumption into a question the taxpayer can answer.

An adjustment can add penalties and interest on top of the extra tax the IRS assesses.

The accuracy-related penalty adds a percentage of an understatement for negligence or a substantial understatement, and the civil fraud penalty is far higher, while interest accrues until the balance is paid. The IRS also has limited time to audit and assess, generally three years from filing, extended to six years when a large amount of income is omitted, and with no limit for a fraudulent or unfiled return. If an adjustment leads to unpaid tax, the IRS can eventually pursue collection, including a levy that may be challenged through the asset seizure process. These stakes make an accurate, timely response important.

Professional help is most valuable for field audits, large adjustments, foreign-account issues, or any sign the matter could turn criminal.

A tax attorney or CPA can manage communications with the examiner, respond to document requests, and pursue Appeals or Tax Court, and matters involving foreign accounts raise added foreign reporting concerns. If an examiner's questions suggest fraud or intentional wrongdoing, the exposure can extend beyond civil penalties to federal tax crime issues, where representation is essential. Because deadlines are firm and statements can matter later, early advice protects your position. If you are facing a serious or complex audit, consult a professional before responding.

Usually because of a computer score flagging likely errors, a mismatch between your return and the W-2s or 1099s the IRS received, unusually large deductions, or a connection to another audited taxpayer. Some returns are chosen at random. An audit does not automatically mean wrongdoing; it means the IRS wants to verify what was reported.

There are three main types. A correspondence audit is done by mail and focuses on specific items, an office audit is conducted in person at an IRS office, and a field audit takes place at your home or business and is the most thorough. Correspondence audits are the most common and usually the narrowest in scope.

Read it carefully, note the deadline, and gather the records that support the items in question. Respond only to what is asked, keep copies of everything, and avoid volunteering extra information. For a field audit, a large adjustment, or anything that feels serious, consider having a tax professional respond on your behalf.

A Notice of Deficiency is the IRS's formal determination that you owe additional tax, and it gives you a set period, generally 90 days, to petition the U.S. Tax Court without first paying the disputed amount. Missing that deadline can make the assessment final, so the letter should be acted on immediately.

Yes. You can dispute proposed adjustments through the IRS Independent Office of Appeals, which can settle based on the litigation risks, and then, if needed, in the U.S. Tax Court or by paying and suing for a refund. Presenting documentation and a clear legal position is key to reducing or defeating an adjustment.

Generally three years from when the return was filed. That extends to six years if a large portion of income was omitted, and there is no time limit for a fraudulent return or one that was never filed. Because these periods vary, keeping records for several years is prudent, especially for complex returns.

It can. An adjustment often carries accuracy-related penalties and interest, and a fraud penalty in serious cases. Most audits are civil, but signs of intentional wrongdoing can lead to a criminal referral. If an examiner's questions point toward fraud, it is important to get legal representation before responding further.

Not for every audit, but professional help is valuable for field audits, significant adjustments, foreign-account issues, or any hint of fraud. A tax attorney or CPA can handle communications, protect your rights, and pursue Appeals or Tax Court. Representation is especially important when penalties are large or criminal exposure is possible.